The camera meter is set correctly by the new Ektachrome 100D cartridge so no adjustment is necessary.

If you must recalibrate it, the potentiometer to adjust the exposure meter is under the trim between the cartridge door and the 18/24 FPS selector. The whole side cover of the camera needs removal to access the potentiometer.

There is no backlight button but an "EE lock." This is a spring -return rotary switch by the lens barrel that fixes the aperture set by the TTL metering as long as it is pushed. On release the aperture returns to auto control set by the metering.

This is another excellent design by Canon. One of the most popular of Super 8 sound cameras, it was launched around 1976 after the first wave of sound cameras from Kodak, Chinon and Bell & Howell in the 1974-75 period and significantly more advanced. Canon later launched sound versions of its 814 and 1014 designs which were high-end designs and much more expensive. It's similar to the 514XL silent camera with the same 5:1 zoom lens plus recording electronics built into the base and an additional 24 fps running speed. Not too heavy, well balanced in the hand, with a sharp lens and ultra clear viewfinder. The viewfinder like those of the 310XL and 514XL is slightly small though but you soon get used to this. Due to its simple automated concept there is no metering manual override except for an EE lock so its not really suitable for Ektachrome 64T or Vision3 500 film. The CCA filter is removed automatically by daylight film such as Ektachrome 100D - Paul814